Riddle: Root Causes of catastrophic engine failure

[GS-T drop top]

Riddle:

You are driving your car that you just got out of a shop. You had installed-- a FMIC, 50 trim turbo, 660 injectors, profec b, S-AFC I, 255 HP fuel pump, new plugs & wires, ported O2 & exhaust. You had already installed full exhaust piping front to back. When you picked up the car, you paid to have it tuned so as to be safe to ride. An hour later, the check engine light goes on. After further inspection, you find a plug wire not fully plugged to the spark plug. You refit it and the light turns off. You take off for a spirited session of driving. On one go, you floor it to measure the full potential of its power. 1st gear, shift, chichunk, 2nd gear, shift, chichunk, enter long hard third gear pull close to redline, shift chichunk BOOM!

BAM, just like that, engine blows oil all over the engine bay, majoritively on the driver side. Smoke begins pouring out of the engine bay. Your idle is throaty and choking like a smoking 60 y/o lung cancer patient. There is no power at throttle and oil is dripping out your tailpipe accompanied by a cloud of dark smelly smoke. Your fourth cyclinder blows zero after tested and you likely have a melted piston.

Q: What caused it?

 

[bigjangin]

i dunno but the answer is take it back to the shop that screwed it up and make them fix it. This is why I dont trust anyone but myself to work on/tune my car.

 

[GS-T drop top]

I dunno is not the riddle's answer.

You get no prize.

 

[GS-T drop top]

Originally posted by bigjangin
i dunno but the answer is take it back to the shop that screwed it up and make them fix it. This is why I dont trust anyone but myself to work on/tune my car.

I will give you another riddle:

Assuming "I dunno " was a suitable answer (I do believe we are in the ADVANCED 4g63 Tech Engine Performance Forum) If you take it back to the shop, what is to stop them from saying it's not our fault. What if they performed a cursory compression test and determined your 4th cylinder was blowing zero, and simply told you, "you'll have to buy a new block."

 

[Defiant]

The "fault" part is rather dicey- unless you can prove negligence or omission on their part, they weren't the ones with their rather heavy boot on the pedal.

It _sounds_ like #4 went lean. Now, whether that means it was first to go and all of them were on the edge, or if just #4 had an issue with fuel supply is still unanswered.

Next time make the shop find out WHY the CEL came on before even thinking about "spirited" driving.

 

[bigjangin]

this isnt an advanced question, and it isnt in advanced tech. You should have a better idea when the engine is torn down, no one can tell you for sure until then.

 

[GS-T drop top]

The S-AFC was tuned as much as it could be however, the car was running too rich, nonetheless. Instead of working with a 12:1 ratio it could not be leaned out any more so it was running 9:1 (way rich).

So this is thought to have caused the catastrophic detonation whgen the car was making a hard WOT pass, 3rd gear was full throttled, and the car was rich so it heated up the egt and exhaust manifold and ended up melting a piston.

This OR, having a big 50 Trim turbo internally gated maybe it suffered a case of massive boost creep which would have slipped the PSI from 17 pounds to 23-25 = BOom.

So next question is:

How do I lean out the car, the S-AFC has been tuned as much as it will go and we can't bypass it. So, I am told my injectors are too big for my system (660's) and perhaps I should get 550's instead so the car won't run as rich?

Any thoughts?

 

[gsxtacy]

Your oil filter seal blew out like LarryD's did a while back. Only it happened in the middle of your spirited 3rd gear pull and you tossed a rod too.

Check that out. hmmmm.

What do I win?

GSXTACY

 

[bigjangin]

660's should be fine with a safc. Ive helped tune cars with 660's, the safc can handle it fine.

 

[GS-T drop top]

660's I thought would run on that system, but the guy who is tuning my car is saying he can't get it to run any leaner. I have heard of the problem from other forums.

Anyone know about running too rich w/ 660's?

 

[pneumo]

Running too rich at WOT with that setup could be caused by too high fuel pressure or a boost leak.

If it's a boost leak it will make the car run lean at idle and low throttle.


Here's a riddle: a 255 fuel pump without an AFPR will make the car run rich at idle, but has no effect at WOT. A boost leak makes the car lean at idle and rich at WOT. Where do you set the AFC at high and low throttle with 660's?

bigjangin has the answer ^

 

[RuBiCaNT5X]

I've heard both, yes 660cc are too much and no they aren't. With a 50 trim, you would probably be at 90+% duty cycle on 550cc's.. Get DSMLink or this.. http://www.dsmchips.com/2g.html Shitty about your car, man..

 

[Defiant]

Originally posted by GS-T drop top
So this is thought to have caused the catastrophic detonation whgen the car was making a hard WOT pass, 3rd gear was full throttled, and the car was rich so it heated up the egt and exhaust manifold and ended up melting a piston.

Backward. The melting piston and the heat that caused it is what raises the EGT.

 

[BUCK]

Originally posted by gsxtacy
Your oil filter seal blew out like LarryD's did a while back. Only it happened in the middle of your spirited 3rd gear pull and you tossed a rod too.

Check that out. hmmmm.

What do I win?

GSXTACY

I concur that this is the best guess - NOT a Tuning error - it would take a MAJOR dumbass to do all these mods & run the water to oil cooler.

 

[gsxtacy]

I RE-read the whole post and still bet this is what happened.

On 4G63's it happens so fast.

I learned.

I had a Oil Pan plug left finger tight in my 92' TSi FWD and it shelled in less than 2 miles because the plug fell out on a test drive after the timing belt change.

So I know just about how long you have after the low oil psi light comes on. About 2 blocks to shut it off after first seeing it.

GSXTACY

 

[GS-T drop top]

Originally posted by BUCK
I concur that this is the best guess - NOT a Tuning error - it would take a MAJOR dumbass to do all these mods & run the water to oil cooler.

I am not sure I AM GETTING THIS. So you are saying the oil line blew off?
Please advise.

 

[BUCK]

All we are saying is it's a POSSIBILTY you spit an Oil Filter Gasket IF you are still running a Water to Oil Cooler...

http://www.vfaq.com/FAQlocator-index.html

 

[GS-T drop top]

Listen, Y'all, Much love for spitting the DSM Knowledge. Blowin your engine after you drop well over $3.5k is apinful no matter how you look at it.

Consolation Prize = My ride drove faster than I have ever experienced a JDM roll before. And this is comin from a man who's owned a modified pumped up 67 Camaro and 89 gt convertible mustang with heads, cam, exhaust, beat, the works.

This is my first JDM ride and turbo set up I have had and blowin out sucked!!!

But it was kinda awesome too! Cuz that car was FLYING!!!!

Can't wait to get my ride back, it's mad tight and looks better than a poor man's porsche, w/ more personal tuning (with love), that ride is going to be sick as in good.

I have a clean g-st, AND i'VE PUT LOT'S OF LOVE IN IT. So I am just w3aiting til I get it done right so I can roll it and appreciate it.

Any help diagnosing it is welcome.

Cause, now I have already solved the melted piston by putting in a new one. Engine is put together, and engine is idling properly. HOWEVER, the car is running way rich. The issue, I need to solve the richnees problem, cause the S-AFC only can get it to 9:1, NOT, 12:1. Can anyone explain the ratios?

 

[pneumo]

Explain the ratios? It looks like you already know that 9:1 is richer than 12:1. Or are you asking WHY it's so rich? Give us a complete rundown of what's been done to it, and ask the shop that worked on the car if they did any other little tweaks, something that might not get mentioned normally, and let us know what guages you have. Like the guy said, 660cc injectors with a SAFC on a 2G car should give you enough range to compensate. You do know that going downward on the AFC adjustments makes it leaner, right? Just checking

I think it was Mike at RRE that said something like,"your car will never feel faster than right before it blows up"